Jigging process for beneficiation of potassium containing ores



y 5, 1956 E. E. WREGE 2,745,547

JIGGING PROCESS FOR BENEFICIATION OF POTASSIUM CONTAINING ORES Filed Aug. 5, 1952 MIXED ORE BRINE BRINE 2%? SYLVINITE 6 OVERFLOW 2 l7 PULP JIG LANGBEINITE HUTCH 8 CONCENTRATE l3 I PRODUCT A BRINE DEWATERING A0 ['8 STATION DEWATERING /3 STATION LANGBEINITE |4 DEWATERING STATION CRUDE LANGBEINITE 23 A COMMINUTOR FLOTATION OVERFLOW |2-\LANGBE|NITE SUME 5 THICKENER BRINE STORAGE WA T S E INVENTOR.

BY M/M ATTORNEY United States Patent JIGGING PROCESS FOR BENEFICIATION OF POTASSIUM CONTAINING ORES Edgar E. Wrege, Lakeland, Fla., assignor to International Minerals & Chemical Corporation, a corporation or New York Application August 5, 1952, Serial No. 302,780

11 Claims. (Cl. 209-2) The present invention relates to a process for the beneficiation of potash minerals. More particularly, the instant invention relates to a process for the beneficiation of potash minerals by a jigging process.

The term jig applies to a machine for classifying materials of difierent specific gravity by the pulsation of a stream of liquid fiowing through a bed of material.

.The liquid pulsates, or jigs up and down, causing the heavier material to concentrate at the bottom of the jig chamber and the lighter material to rise toward the top of the chamber. The two fractions of materials are drawn off separately.

In the past, jigging has not been used commercially for the beneficiation of potash ores because recovery of the potash bearing constituents at acceptable grades has been very poor. This is caused by the'relatively small differences in specific gravity existing between the potash bearing constituents and the gangue. The main constituents ofpotash ores of the New Mexico .area are sylvite (KCl), specific gravity 2.00; langbeinite (K2804- ZMgSOt), specific gravity 2.83; and halite (NaCl), specific gravity 2.16. The potash ores mined and-refined in the area near Carlsbad, New Mexico, are sylvinite ore, containing sylvite and halite; langbeinite ores, containing langbeinite and halite; and a mixed ore, containing sylvinite and langbeinite ores. Up to the'present date there has been no acceptable commercial process for the treatment of the mixed ore for the recovery of both potash minerals, and as little of this ore as possible is mined and beneficiated because of the low potash recovery which would'be obtained.

It is an object of the instant invention to provide a process for the beneficiation of potash-containing ores y j It is a further object of the instant invention to provide a process for the beneficiation of mixed ores by j It is a further object of the instant invention to provide a process for the recovery of sylvite and langbeinite by jigging of a mixed ore feed material.

These and other objects of the instant invention will become more apparent upon a fuller understanding of the invention as herein set forth.

The present invention, in part, relates to the combination of a jigging process for the separation of mixed ore into a high grade langbeinite ore and a sylvite-containing fraction with processes now in operation for the treatment of sylvite-containing material. Langbeinite and sylvite are the final products recovered from the mixed ore.

In the separation of constituents of ore, for example, langbeinite particles from other constituents, the degree of separation between two particles of like size and shape with different gravities and suspended in a medium will be dependent upon the ratio of the gravity difference existing between the particle and the medium. For exam- 2,745,547 iatented May 15, 1956 ple, the specific gravities of the constituents of mixed ore pulp are as follows:

Specific gravity 'Langbeinite 2.83 Sylvite 2.00 Medium (water) 1.00

Therefore, the degree of separation is proportional to 2.83-1.00 O 1.83 2.00-1.00 yr 1.00

If the medium has a specific gravity of about 1.34, the degree of separation is proportional to 2.831.34 r g r 2.26 2.00-1.34 0.66 1.00

which represents an increase of about 250%.

Although in practicing the instant novel process it is desirable to increase the apparent specific gravity of the medium, such increase should not be accompanied by an appreciable increase in the viscosity of the medium .because increasing the viscosity of the medium decreases the speed and efficiency of the separation. It has been found that when the apparent gravity of the medium is increased by suspending fine particles of langbeinite in the medium, for example, langbeinite particles smaller than about 48 mesh, there is no substantial increase in the viscosity of the medium. In practicing the instant process, the medium should have an apparent gravity of between about 1.3 and about 2.0, preferably between about 1.6 and about 2.0.

In carrying out the instant novel process, a pulp of mixed ore in a medium of controlled apparent gravity is subjected to a jigging operation.

In the preparation of the feed pulp, the, mixed ore is admixed with an aqueous brine in which the ore constituents will not dissolve under the prevailing conditions. It has been found that a reject liquor from sylvitelangbeinite base exchange processes to which sylvite has been added until the brine is saturated with respect'to sylvite, is a preferred high density brine having a specific gravity of about 1.34. The above mentioned brine has a higher density than brines prepared from sylvinite which are employed in flotation and other conventional potash beneficiation processes. Mixed ore brine, which refers to an aqueous solution prepared from a mixture of langbeinite and sylvinite ores, and which is saturated .with respect to sylvite and halite at the temperature of operation, is another brine which may be employed. The brine likewise has a specific gravity, when free of suspended solids, about the same as the above-mentioned reject liquor saturated with sylvite. These brines are hereafter referred to in the description and claims as high density brines.

3 cute and is admixed with high density brine and langbeinite particles having a mesh size smaller than about 48 mesh. The slurry density of the resulting pulp is between about 40% and about 70% solids by weight, preferably between about 50% and about 60% solids by Weight. The pulp is then subjected to the action of a jig.

Any type of commercially available jig may be employed in practicing the instant invention, however, the Jeffrey Baum jig in which the separation takes place on the down stroke is preferred. The preferred design of the jig is an all-hutch jig, although a combination draw and hutch jig can be employed. The jig may be of one compartment but one of three or four compartment design is preferred.

In another embodiment a three compartment jig is employed. In such a case, the concentrate from the first compartment comprises essentially langbeinite and some halite. The concentrate is subjected to classification in order to separate the brine from the crude langbeinite. This crude longbeinite is then water washed to remove the halite. The washed langbeinite fraction contains between about 85% and about 95% of the longbeinite present in the feed. The overflow from the first compartment of the jig is conducted to the second compartment of the jig. The longbeinite which was not recovered in the first compartment is recovered in the second compartment, for example, as the hutch product. This fraction may contain a substantial amount of sylvinite depending upon the degree of liberation of sylvite and halite. This fraction if desired can be further comminuted to liberate the langbeinite from the sylvite and the halite and recycled through the jig. The third compartment of the jig results in the recovery of any longbeinite escaping the second compartment while the overflow from the third compartment contains mainly sylvite and halite. This product is subjected to any conventional froth flotation operation to recover sylvite therefrom. In a fourth compartment is employed, it is possible to obtain an overflow which is principally high grade sylvite.

Referring to the fiowsheet which illustrates a continuous embodiment of the instant invention, the comminuted mixed ore 1 having a mesh size of about x mesh is pulped with a brine stream 3 containing fine langbeinite (48 mesh) and suflicient clarified high density brine 2 in pulp box 4 in which the mixture is vigorously agitated to obtain uniformity of composition. Suflicient brine is added to obtain a slurry density of between about 40% and about 70% solids by weight. The pulp 5 passes from the pulp box 4 to the three compartments of jig 6. Suflicient additional clear brine 7 is added to the jig at this point to convey the solids through the jig under conventional operating conditions and proper pulp densities. In operating the jig the fre quency of the jig stroke and the pulsations employed depend on the quality and particle size of the feed material. I When the three compartment jig 6 is used, a concentrate 8 containing largely langbeinite and some halite is recovered as the hutch produce of the first compartment. Concentrate 8 is subjected to dewatering at station 9 in order to separate brine 10 from crude langbeinite 11. The crude dewatered langbeinite product 11 which analyzes between about 80% and about 90% langbeinite and represents between about 85% and about 95% recovery of langbeinite from the feed, is conducted to langbeinite refining operation 12 where high grade langbeinite is produced by water washing the halite from the langbeinite. If desired or deemed advantageous, part of the langbeinite recovered can be comminuted and recycled to pulp box 4 to increase the apparent specific gravity of the liquid medium to the desired degree.

The overflow from the first compartment of the jig 6 is treated in the second compartment for recovery of unliberated langbeinite. The langbeinite is not recovered in the first compartment is recovered in the second com- 4 partment as the hutch product 13. This produce 13 contains considerable halite and after dewatering at station 14 is ground in comminutor 15 to liberate the langbeinite from the halite and sylvite. The comminutor discharge is recycled with brine 23 to the pulp box 4 and then reintroduced to the first compartment of jig 6.

The third compartment of jig 6 recovers any unrecovered langbeinite escaping the second compartment. Hutch product 16 from the third compartment can be processed with the hutch middling product 13 from the second compartment if the langbeinite content is appreciable, or product 16 can be combined with 'syvinite overflow product 17 from the third compartment if the sylvite content of product 16 is appreciable.

The sylvinite overflow 17 from the third compartment is subjected to dewatering at station 18 and the crude sylvinite so separated then conducted to a flotation section 19 where sylvite is recovered by standard flotation practice. When a jig with a fourth compartment is employed, an overflow which is principally sylvite, instead of sylvinite, is obtained.

I It is important to the jigging operation to maintain the lowest possible slime concentration in the brine because the presence of slime increases the viscosity of the medium without appreciably increasing the gravity, therefore, the overflows from the dewatering stations 9, 14 and 18 which stations may employ rake or spiral classifiers or dewatering drags, are clarified of suspended slimes in thickener 20. The overflow 21 of the thickener 20 is conducted to storage 22 from which it is pumped to the desired points in the process.

As a specific example of the instant invention, the following serves as an illustration but it is not intended that the scope of the instant invention be limited thereto.

EXAMPLE A feed material of deslimed ore containing langbeinite and sylvinite sized to about to 0 mesh was pulped with mixed ore brine saturated with respect to sylvinite in suflicient amount to produce a slurry density of about 50% solids by weight. After thorough wetting of the particles, suflicient brine was added to obtain a slurry density of between about 15% and about 20% solids by weight. The pulp was then fed to a Jeflery Baum jig having 3 jigging'compartments in series. The hutch products from the second and third compartments were recycled, the product being that obtained from the hutch of the first compartment. The following table shows the weight per cent of langbeinite, sylvite and halite in the feed and in the products recovered. The recovery of langbeinite was about and of sylvite about 98%. The total K20 recovery was about 94%.

Table Weight Percent Fraction Material of Feed 7 Lang I I beim-te sylvite Hahte Feed:

+20 mesh 78. 2 44. 20 8. 81 43. 54 --20 mesh 21. 8 42. 71 11. 03 43. 28

Total 100. 0 43. 9 9. 3 43. 49

Langbeinite Product, First Compartment:

+20 mesh 73. 2 92. 76 0. 21 4. 78 ---20 mesh 26. 8 80. 39 0. 39 16. 35

Total 100. 0 89. 40 0. 3 7. 89

sylvinite Product Third Compartment:

Total 100. 0 7. 2 14. 90 77. 20

Having thus fully described the character of the instant invention, what is desired to be secured by Letters Patent is:

1. A process for the beneficiation of mixed ores containing langbeinite and sylvinite which comprises preparing a pulp of comminuted ore particles, suspending said comminuted ore particles in high density brine containing ore particles too finely divided to be separated during processing and in sufiicient quantity to produce a medium having an apparent specific gravity above 1.3, but below 2.0, subjecting the resulting pulp to a jigging operation, and separately collecting a langbeinite enriched fraction and a sylvite enriched fraction therefrom.

2. A process for the beneficiation of mixed ores containing langbeinite and sylvinite which comprises comminuting the ore to substantially completely liberate the particles, preparing a pulp of the comminuted ore particles to be separated, suspended in a high density brine in which finely divided langbeinite particles substantially unseparated during processing and substantially insoluble are maintained in sufficient amount in the brine to produce an apparent specific gravity above 1.3, but below 2.0, subjecting said pulp to a jigging operation and separately collecting a langbeinite enriched fraction and a sylvite enriched fraction therefrom.

3. A process as in claim 2 wherein the jigging operation effects a separation of langbeinite particles from sylvite and halite particles primarily on the suction stroke.

4. A process for the beneficiation of mixed ores containing langbeinite and sylvinite which comprises preparing a pulp of the comminuted ore particles in high density brine, adding to the pulp langbeinite particles smaller than about 48 mesh in sufiicient quantity to produce an apparent specific gravity above 1.3, but below 2.0, in the brine, subjecting the resulting pulp to a jigging operation in which the separation of the langbeinite particles from the sylvite particles takes place primarily on the suction stroke, and separately collecting a langbeinite enriched fraction and a sylvite enriched fraction therefrom.

5. A process for the beneficiation of mixed ores containing langbeinite and sylvinite which comprises comminuting the ore to substantially completely liberate the langbeinite and the sylvite particles, desliming said comminuted ore, preparing a pulp of the deslimed ore particles suspended in sutficient high density brine in which the ore particles are substantially insoluble to produce a pulp of a solids density of between about 40% and about 70%, adding to the resulting pulp sufficient langbeinite particles smaller than about 48 mesh to produce an apparent specific gravity above 1.3, but below 2.0 in the resulting brine, subjecting the resulting pulp to a jigging operation in which the separation of the langbeinite particles from the sylvite particles takes place largely on the suction stroke, and collecting a langbeinite enriched fraction therefrom.

6. A process for the beneficiation of mixed ores containing langbeinite and sylvinite which comprises comminuting the ore to substantially completely liberate the sylvite and langbeinite particles, preparing a pulp of the comminuted ore particles with a high density brine in which the ore particles are substantially insoluble, adding langbeinite particles which are smaller than about 48 mesh to the pulp in sufiicient quantity to produce an apparent specific density above 1.3, but below 2.0 in the brine, subjecting the resulting pulp to the action of a primary jigging operation in which the separation of the langbeinite particles from sylvite particles takes'place on the suction stroke, collecting a langbeinite enriched fraction, subjecting the fraction containing sylvite particles which overflows from the primary jig compartment to a secondary jigging operation in which the separation of additional quantities of langbeinite particles from sylvite particles takes place on the suction stroke, and to separately collect a langbeinite enriched fraction and a sylvite enriched fraction from the mixed ore feed.

7. Theprocess of claim 6 wherein a langbeinite enriched fraction from the secondary jigging operations is comminuted and recycled to the feed to the primary jigging operation.

8. A process for the beneficiation of mixed ores containing langbeinite and sylvinite which comprises comminuting the ore to substantially completely liberate the sylvite and langbeinite particles, preparing a pulp of the comminuted ore particles suspended in a medium having an apparent density above 1.3, but below 2.0, subjecting the resulting pulp to the action of a primary jigging operation in which the separation of the langbeinite particles from sylvite particles takes place on the suction stroke, collecting a langbeinite enriched fraction, subjecting the fraction containing sylvite particles which overflows the primary jig to a secondary jigging operation in which the separation of additional quantities of langbeinite particles from sylvite particles takes place on the suction stroke, collecting a second langbeinite enriched fraction and a sylvite enriched fraction therefrom, conducting the sylvite enriched fraction to a third jigging operation in which the separation of the heavier particles takes place on the suction stroke, and collecting a second sylvite enriched fraction therefrom.

9. The process of claim 8 wherein the langbeinitecontaining fraction collected from the secondary jigging operation is comminuted and recycled to the feed which is conducted to the primary jigging operation.

10. A process for the beneficiation of mixed ores containing langbeinite and sylvinite which comprises comminuting the ore to substantially completely liberate the constituents of the ore, preparing a pulp of ore particles suspended in sufiicient high density brine in which the ore particles are substantially insoluble, to produce a pulp of solids density of between about 40% and about adding sufiicient langbeinite particles having a mesh size smaller than about 48 to the pulp to produce an apparent specific gravity above 1.3, but below 2.0 in the resulting brine, subjecting the resulting pulp to a primary jigging operation in which the separation of langbeinite particles from a sylvite enriched fraction takes place on the suction stroke, collecting a langbeinite enriched fraction, subjecting the fraction containing sylvite particles from the primary jig to a secondary jigging operation in which the separation of additional quantities of langbeinite particles takes place on the suction stroke, and separately separating a langbeinite enriched fraction and a sylvite enriched fraction therefrom.

11. A process for the beneficiation of mixed ores containing langbeinite and sylvinite which comprises comminuting the ore to substantially completely liberate the sylvite and langbeinite particles, preparing a pulp of the comminuted ore particles suspended in sufiicient high density brine in which the ore particles are substantially insoluble to produce a slurry density of between about 40% and about 70% solids by weight, adding sufiicient langbeinite particles having a mesh size smaller than about 48 to the pulp to produce an apparent specific gravity above 1.3, but below 2.0 in the resulting brine, subjecting the resulting pulp to the action of a primary jigging operation in which the separation of the langbeinite particles from the sylvite particles takes place on the suction stroke, separately collecting a langbeinite enriched frac tion and a sylvite enriched fraction, subjecting the sylvite enriched fraction to a secondary jigging operation to produce a second langbeinite enriched fraction and a second sylvite enriched fraction, comminuting and recycling the second langbeinite enriched fraction to the feed to the primary jigging operation, conducting the second sylvite enriched fraction to a third jigging operation in which the separation of the heavier particles takes place on the suction stroke, and collecting final sylvite enriched fraction therefrom.

(References on following page) References Cited in the file of this patent Bureau of Mines Report of Investigations 3271, February 1935, pp. 1 to 5.

UNITED STATES PATENTS Bureau of Mines Report of Investigations 3300, Februls Mar. 19, y PP. 1 to 3. 2214206 Rasor Sept- 1940 5 Engineering Inf. Mining Journal, vol. 141, No, 2,

OTHER REFERENCES 81, 82.

Article by B. M. Bird entitled Without Suction, Coal Bureau of Mlnes Information Circular, 7277, April Age, vol- 38 1933. p in Division 55. 

1. A PROCESS FOR THE BENEFICIATION OF MIXED ORES CONTAINING LANGBEINITE AND SYLVINITE WHICH OCMPRISES PREPARING A PULP OF COMMINUTED ORE PARTICLES, SUSPENDING SAID COMMINUTED ORE PARTICLES IN HIGH DENSITY BRINE CONTAINING ORE PARTICLES TOO FINELY DIVIDED TO BE SEPARATED DURING PROCESSING AND IN SUFFICIENT QUANTITY TO PRODUCE A 